A couple celebrates upon hearing the U.S. Supreme Court has struck down the Defense of Marriage Act at City Hall on June 26 in San Francisco. / Justin Sullivan, Getty Images

by Susan Page, USA TODAY

by Susan Page, USA TODAY

WASHINGTON - The nation's rapidly changing attitudes toward homosexuality have been reflected in dramatic changes in the views of presidents, the rules for military service and the policies defining families.

And now, in the Supreme Court.

The high court ended its term Wednesday with the most far-reaching and hotly awaited decisions of the year. It overturned the federal Defense of Marriage Act, which will bring sweeping changes to the way Social Security and other benefits are awarded, and it opened the door to resume same-sex marriages in California, the country's most populous state.

What's more, the rulings underscore how attitudes toward a fundamental cultural issue have changed in an unprecedentedly short period of time. The repercussions of Wednesday's action are likely to fuel those trends in everything from national politics to the daily lives of millions of Americans.

"We have to acknowledge the phenomenal progress we've made, and with these two historic rulings we've taken two giant steps forward toward the American promise of equal justice under law," Chad Griffin, president of the Human Rights Campaign, said in an interview with USA TODAY. "But we're still not there. We're still not all the way there. We celebrate today, and tomorrow we wake up and fight like hell until full equality is achieved in all 50 states."

Gay-rights advocates such as the Human Rights Campaign didn't get everything they wanted in the court decisions. In the challenge to California's Proposition 8 ban on gay marriage, the court ruled that the plaintiffs didn't have the standing to sue. That means the decision doesn't affect other states.

Even so, by rejecting the appeal, the high court sent the case back to California, where both a state court and federal district court have struck down Prop 8, passed in 2008. Earlier that year, the California Supreme Court had endorsed same-sex marriage. While the timing ahead wasn't immediately clear, California is poised to rejoin 12 other states and the District of Columbia in permitting gay men and lesbians to wed.

And in another 5-4 decision, the court ruled that the Defense of Marriage Act, which barred the federal government from recognizing gay marriages that had been sanctioned by states, violated the Constitution's equal protection clause. That new constitutional standard for sexual orientation surely will be used in challenges in states that now ban gay marriage.

Consider the turnaround in public opinion since President Clinton signed the Defense of Marriage Act in 1996, which his aides saw as a political necessity two months before his re-election. That year, just 27% in a USA TODAY/Gallup Poll said same-sex unions should be recognized by law as valid, with the same rights as traditional marriages. Sixty-eight percent said they shouldn't.

In a Pew Research Center poll last month, 51% backed allowing gay men and lesbians to marry, the first time it had majority support in that poll.

There continues to be significant opposition: 46% opposed legalizing gay marriage. But even most opponents said that legal recognition was now "inevitable."